This interdisciplinary project involves the interinstitutional collaboration of three principal investigators: Dr. Van C. Mow, Rensselaer Polytechnic Institute, Dr. Alan J. Grodzinsky, Massaccusetts Institute of Technology and Dr. David R. Eyre, Children's Hospital Medical Center, Harvard Medical School. In general, the RPI group will study all of the biomechanical and functional properties of articular cartilage, the MIT group will study the electromechanical and chemico-mechanical properties and the CHMC group will pursue all biochemical characterizations and modifications of normal and animal osteoarthrotic tissues. Rensselaer Polytechnic Institute will be the primary grantee institution and MIT and CHMC will subcontract from RPI. In this proposed project, we are seeking to determine the correlation between the biochemical composition and structural changes of articular cartilage specimens and their biomechanical and electromechanical properties. In so doing, we would have determined: (1) the appropriate intrinsic material moduli for the cartilage matrix, (2) the permeability functions, (3) streaming potentials, (4) various matrix electromechanical transduction coefficients and (5) the frictional and lubrication characteristics of articular cartilage. All these properties will be statistically correlated to the biochemical composition of normal tissue: (1) water content, (2) collagen content and type, (3) uronic acid content, (4) glycosaminoglycan content and type and (5) protein content; and specific biochemical alterations of matrix macromolecule conformations: (1) proteoglycan extraction, (2) crosslinking, (3) enzymatic digestions and (4) synovitis induced alterations. Experimental osteoarthrotic animal models will be used to generate osteoarthrotic tissues for all biomechanical, electromechanical and biochemical characterizations. From these experimental data, we hope to develop an understanding of matrix macromolecular interactions for normal and osteoarthrotic tissues. Defects in these molecular interactions will result in a tissue of inferior biomechanical properties. Defects in these biomechanical properties will result in an inferior functional characteristic: friction and lubrication. In sum, the aim of this prepared research is to develop a quantitative molecular and structural model for normal and osteoarthrotic articular cartilage behavior and function.